Fuel injection system



Sept 11, 1952 T. M. BALL 3,053,313

FUEL INJECTION SYSTEM Filed April 9, 1958 array/VIAS',

United States Patent Office 3,053,313 Patented Sept. 11, 1962 3,053,313FUELINJECTEON SYSTEM Thomas M. Ball, Bloomfield Hills, Mich., assignerto j Chrysler Corporation, Highland Park, Mich., a corporation ofDelaware Filed Apr. 9, 1958, Ser. No. 727,423 7 Claims. (Cl. 15S-36.3)

This invention relates to a fuel injection system and in particular tomeans for metering fuel to the cylinders of an internal combustionengine in amounts determined by engine operating conditions.

Although the invention is concerned mainly with automotive engines, itis anticipated that the disclosed type of fuel metering system may beused on other types of internal combustion engines.

lt is conventional in fuel injection systems to supply fuel under pumppressure to a metering system which regulates the fuel low to a numberof fuel injection nozzles in accordance with the engine speed and loadrequirements. In such systems it is common to meter the fuel to thenozzles through one or more needle valve controlled metering orificeswhich are subject to regulation by various atmospheric and engineoperating parameters, including speed and load as aforesaid. Among theproblems encountered by such systems is the pressure drop across themetering system which often results in fuel vaporization and cavitationon the downstream side of the system, particularly on hot days duringconditions of comparatively light load and fuel flow. In consequence ofvapor formation and of comparatively low pressure downstream of themetering system, uneven fuel flow to the nozzles and poor nozzlee'iciency results.

It is accordingly an object of this invention to provide an improvedfuel distributing system which utilizes the principle of supplying fuelat optimum pump pressure in parallelism with both a fuel metering systemand the fuel injection nozzles of an internal combustion engine and forreturning the excess fuel to the fuel tank via conduit means downstreamof the metering system, thereby to maintain an optimum fuel pressuredownstream of said metering system and also to assure an optimum ow offresh fuel through said metering system particularly at light loads,whereby over heating of the fuel and vapor formation downstream of themetering system is minimized.

It is another object of this invention to provide a fuel distributingsystem which returns excess fuel to the fuel tank in accordance with theengine requirements as transmitted to the fuel distributing system bythe speed of rotation of the engine crankshaft and the pressure of thegases in the intake manifold of the engine.

It is still another object of this invention to provide a fueldistributing system wherein the amount of fuel returned to the fuel tankis a function of two return flow metering needles one of which acts inaccordance with engine speed and the other of which acts independentlyand in accordance with the manifold pressure.

It is another object of this invention to provide a fuel distributingsystem wherein vapor formed in the fuel tank or feed conduit and carriedby the feed fuel is purged from said fuel by continuously returning alarge portion of said fuel back to the fuel source.

For the purpose of particularly describing the principal features of theinvention, reference will be made to the accompanying drawing wherein:

The `FIGURE is a schematic representation of the fuel circulatory systemshowing the speed and load sensory mechanism.

Referring to the drawing, -86 represents a fuel distribution chamber orrosette having fuel outlets 88 thereon and is connected to a fuel tankby a feed conduit 92 communicating with said chamber through inlet 93. Aconstant delivery fuel pump 94 supplies fuel under pressure to chamber86. A primary return flow outlet 96 having a tapered orifice 98 connectschamber 86 with a primary fuel return flow conduit 100l whichcommunicates with fuel tank 90. A pressure regulator 102 connectingconduits 92 and 100 returns some excess fuel to the tank and eliminatesa building up of excessive pressure in chamber 86.

A primary return flow metering needle 104 has a tapered end 106 shapedto 4fit snugly into orice 98 of port 96. A flexible diaphragm 10S ofcorrosion resistant material is secured to needle 104 by bushing 110. Anexpansion rib 112 may be provided on diaphragm 108. A housing 114comprised of two sections 116 and 118 slidably receive needle 104 inbushings 120l and 1.22 respectively. Housing 114 is secured againstmovement relative to chamber 86. Vent 124 opens one side of diaphragm100 to atmosphere to prevent compressed air resistance to movement ofdiaphragm 108. A secondary return flow conduit 126 having a constriction128 therein connects chamber S6 to chamber 130` in housing 114 through abranch 136 of conduit 126 and allows a substantial portion of thepressure in said chamber to act on diaphragm 108.

A secondary return llow outlet 132 opens into conduit 126 and isprovided with tapered orifice 134. Constriction 138 in conduit 126 isinterposed between said secondary outlet and the fuel tank. A secondaryreturn flow metering means or needle 140 having tapered end 142 which isshaped to tit snuglyvinto orifice 134 is secured to flexible diaphragm144 by bushing 146. Diaphragm 144 may be provided with expansion rib148. A housing having portions 152 and 154 slidably receive needle 140in bushings 156 and 158 respectively and vents one side of diaphragm 144to the atmosphere through aperture 172 to again prevent air resistance.A manifold pressure conduit 160 opens into chamber 162 in housing 150and is connected at its other end to the low pressure portion of anintake manifold of an internal combustion engine to transmit pressuresignals in the manifold to the chamber i162 to exert a force ondiaphragm 144 proportional to the manifold pressure. A spring 164 may beinterposed between diaphragm 144 and housing portion 152 to provide aslight resistance against movement of diaphragm 144 toward port 132.Suitable means such as screws 168 and 170 are provided to clamp housingportions 152 and 154 together.

Opposite the tapered end 106 metering needle 104 is provided with a pairof collars 60 and 62. A speed sensor generally designated at 64 issecured to the engine crankshaft 66 to rotate therewith. A pair of arms68 and '70 having flyweights 72 and 74 respectively are pivotallymounted at 76 and 78 on the speed sensor housing 80. Arms 82 and 84integral with arms 68 and 70 are loosely tted between collars 60* and 62and abut collar 60 during the normal operation of the engine. Since arms63 and 70 are integral with arms 82 and 84 respectively, they are alsopivotal about points 76 and 7 S respectively.

In the operation of the fuel distributing system, pump 94 supplies aconstant amount of fuel to chamber 86 when the engine is started.Portions of this fuel will be returned to the tank through outlets 96and 132. Another portion of said fuel will flow through conduit 126 tochamber 130 wherein it will exert a force on diaphragm 108 and urgeneedle 104 away from orifice 9S. However, as the engine is being crankedand as the first portions of fuel ignite in the cylinders, the speedsensor 64 will produce a force on needle 104 tending to urge it towardorifice 98. As the engine approaches its idling speed the force onneedle 104 produced by the speed sensor 64 on collar 60 slightly exceedsthe force on said needle produced by lche fuel pressure on diaphragm108. However, simultaneously with the application of these forces to theneedle 104, the intake manifold pressure decreases and the greateratmospheric pressure on diaphragm 144 urges needle 140` toward outlet132. As the return ow through outlet 132 decreases, the fuel pressure inchamber 130 builds up sufficiently to maintain needle 104 the correctdistance from outlet 96 to allow the engine to idle. i

As the engine throttle is opened, a pressure increase occurs on themanifold side of diaphragm `144 tending to urge needle 140 to an openposition to allow the return of fuel through outlet `132. Upon thereturn of a portion of the fuel through outlet 132 which fuel normallyows to chamber 130, the pressure on the fuel side of diaphragm 108decreases and allows the speed sensor 64 to urge needle 104 closer toorifice 98 which causes more fuel to be retained in chamber 86 andconsequently greater fuel flow to the cylinders. As the pressure inchamber 130 gradually attains the pressure in chamber S6 the needle 104becomes stationary at a closer distance to the orifice 98. Any furtheropening of the engine throttle will again provide a pressure dropbetween chambers 86 and 130 and again cause the needle 104 to be urgedcloser to orifice 98.

As the throttle is closed or partially closed, a pressure decreaseoccurs in chamber #162 of the load sensor and causes needle 140 to movecloser to orifice 134 and retard the flow of retunn fuel through outlet132. As this occurs, the pressure in chamber 130l will increase andcause needle 104 to move further away from orifice 98 and allow morefuel to return to the tank which will result in a decreased fuel supplyto the cylinders and a deceleration of the engine. Restrictions 128 and138 are provided in conduits l126 and 136 respectively and provide aslower rate of fuel flow in the vicinity of outlet 132 to allow smallchanges in manifold pressure to effectively vary the flow of return fuelthrough outlet 132. These restrictions tare desirable to produce agreater range of more accurate pressure variations on diaphragm 108 witha smaller degree of travel of the needle 140. Restriction 138 alsoinsures a limit to the amount of fuel that can be returned to the tankthrough outlet 132 in the event that needle 140 should override adesirable distance from outlet 132.

The structural details herein disclosed for the purpose of illustratingmy invention may be widely varied without departing from the substanceof the invention, or sacrificing the advantages thereof, and hence I donot limit my invention to the specific structure disclosed, except tothe extent clearly indicated in specific claims, but reserve all suchvariations, modications and equivalents .as fall within the spirit andpurview of the claims.

I claim:

1. In a return flow fuel metering system for an internal combustionengine, a fuel distributing chamber having a fuel inlet connected with afuel source and a plurality of fuel outlets adapted to be operativelyconnected with said engine, a return flow conduit connecting saidchamber with said source, a return ow valve for regulating the flow ofreturn fuel in said return ow conduit from said chamber to said source,engine speed responsive means operatively connected with said valve forprogressively closing the latter with increasing speed, fuel pressureresponsive means operatively connected with said valve for progressivelyopening the latter with increasing fuel pressure applied to saidpressure responsive means, duct means connecting said pressureresponsive means with said chamber for applying the pressure at thelatter to said pressure responsive means, said duct means having arestriction therein, and means for controlling the pressure applied tosaid pressure actuated means by said duct means comprising a second ductmeans in communication with the first named duct means at a locationbetween said restriction and said pressure responsive means and being incommunication with said source, a second valve for regulating the flowof fuel from said location to said source, and engine load responsivemeans operatively connected with said second valve foi progressivelyopening the latter with increasing load, thereby to decrease thepressure applied to said pressure actuated means with increasing load.

2. In a return flow fuel metering system on an internal combustionengine, a fuel distributing chamber having a fuel inlet connected with afuel source and a plurality of fuel outlets adapted to be operativelyconnected with said engine, a return `flow conduit connecting saidchamber with said source, a return flow valve for regulating the flow ofreturn fuel in said return flow conduit from said chamber to saidsource, engine speed responsive means operatively connected with saidvalve and operable at a speed proportional to the speed of said enginefor progressively closing said valve with increasing speed, fuelpressure responsive means operatively connected with said valve forprogressively opening the latter -with increasing Afuel pressure appliedto said pressure responsive means, duct means connecting said pressureresponsive means with said chamber for applying the pressure at thelatter to said pressure responsive means, said duct means having arestriction therein, and means for controlling the pressure applied tosaid pressure actuated means 'by said duct means comprising a secondduct means in communication with the first named duct means at alocation between said restriction and said pressure responsive means andlbeing in communication with said source, a second valve `for regulatingthe flow of fuel from said location to said source, and engine loadresponsive means operatively connected with said second valve and `beingin communication with the intake manifold pressure of said engine andresponsive thereto for progressively opening said second valve withincreasing load on said engine, thereby to decrease the pressure appliedto said pressure actuated means with increasing load.

3. In a return flow fuel metering system for an internal combustionengine, a fuel distributing chamber having a fuel inlet connected Iwitha fuel source and a plurality of fuel outlets adapted to lbe operativelyconnected with said engine, means for supplying fuel under pressure fromsaid source to said chamber through said inlet, a return ow conduitconnecting said chamber with said source, a return ow valve forregulating the flow of return fuel in said return flow conduit from saidchamber to said source, engine speed responsive means operativelyconnected with said valve for progressively closing the latter withincreasing speed throughout the operating speed range of said engine,fuel pressure responsive means operatively connected with said valve`for progressively opening the latter with increasing fuel pressureapplied to said pressure responsive means, duct means `connecting saidpressure responsive means with said chamber for applying the pressure atthe latter to said pressure responsive means, said duct means having arestriction therein, and means `for controlling the pressure applied tosaid pressure actuated means by said duct means comprising a `secondduct means in communication with the first named duct means at alocation between said restriction and said pressure responsive means andbeing in communication with said source, a second valve for regulatingthe flow of fuel from said location to said source, and engine loadresponsive means operatively connected with said second valve forprogressively opening the latter `with increasing load, thereby todecrease the pressure applied to said pressure actuated means withincreasing load.

4. -In a return ow fuel metering system for an internal combustionengine, a -fuel distributing chamber having a fuel inlet connected witha fuel source and a plurality of fuel outlets adapted to be operativelyconnected with said engine, means for supplying fuel under pressure fromsaid source to said chamber through said inlet, a return flow conduitconnecting said chamber with said source, a return flow valve forregulating the flow of return fuel in said return ilovv conduit fromsaid chamber to said source, engine speed responsive means operativelyconnected with said valve for progressively closing the latter Withincreasing speed throughout the operating speed range of said engine,fuel pressure responsive means operatively connected with said valve`for progressively adjusting the latter with increasing lfuel pressureapplied to said pressure responsive means, duct means connecting saidpressure responsive means with said chamber `for applying the pressureat the latter to said pressure responsive means, said duct means havinga restriction therein, a second duct means in communication with theiirst named duct means at a location between said restriction and saidpressure responsive means and being in communication with said source, asecond valve for regulating the iiow of fuel from said location to saidsource, and engine load responsive means `operatively connected withsaid second valve for adjusting the latter to `control the pressureapplied to said pressure actuated means to close the first named valveprogressively with increasing engine load.

5. In a return flow fuel metering system on an internal combustionengine, a fuel distributing chamber having a fuel inlet connected With afuel source and a plurality of fuel outlets adapted yto be operativelyconnected with said engine, means for supplying fuel under pressure fromsaid source to said chamber through said inlet, a return flow conduitconnecting said chamber with said source, a return flow valve forregulating the flow of return fuel in said return flow conduit from saidchamber to said source, engine speed responsive means operativelyconnected with said valve for progressively closing the latter Withincreasing speed throughout the operating speed range of said engine,fuel pressure responsive means operatively connected with said valve forprogressively adjusting the latter with increasing fuel pressureKapplied to said pressure responsive means, duct means connecting saidpressure responsive means with said chamber for applying the pressure atthe latter to said pressure responsive means, said duct means having arestriction therein, a second lduct means in communication with thefirst named duct means at a location between said restriction and saidpressure responsive means and being in communication with said source, asecond valve for regulating the ow of fuel from said location to saidsource, and engine load responsive means operatively connected with saidsecond valve and being in communication with the d intake manifoldpressure of said engine and responsive thereto for adjusting said secondvalve to control the pressure applied to said pressure actuated means toprogressively close the first named valve With increasing engine load,thereby to decrease the pressure applied to said pressure actuated meanswith increasing load.

6. ln a return iiow fuel metering system on an internal combustionengine, a fuel distributing chamber having a fuel inlet connected With afuel source and a plurality of fuel outlets adapted to be operativelyconnected with said engine, means for supplying fuel under pressure fromsaid source to said chamber through said inlet, a return ilow conduitconnecting said chamber with said source, a return ow valve forregulating the iiow of return fuel in said return flow conduit from saidchamber to said source, engine speed responsive means operativelyconnected with said valve and operable at a speed proportional -to thespeed of said engine for progressively closing said valve withincreasing speed throughout the operating speed range of said engine,fuel pressure responsive means operatively connected lwith said valvefor progressively adjusting the latter With increasing fuel pressureapplied to said pressure responsive means, duct means connecting saidpressure responsive means Wit-h said chamber for applying 4the pressureat the latter to said pressure responsive means, said duct means `havinga restriction therein, a second `duct means in communication lwith thefirst named duct means at a location between said restriction and saidpressure responsive means and being in communication with said source, asecond valve for regulating the flow of fuel from said location to saidsource, and engine load responsive means operatively connected with saidsecond valve for adjusting the latter to control the pressure applied tosaid pressure actuated means to close hedirst named valve progressivelywith increasing engine 7. In the combination according to claim 6, saidload responsive means comprising pressure responsive means responsive tothe intake manifold pressure of said engine.

References Cited in the le of this patent UNITED STATES PATENTS2,412,289 Pugh et al Dec. 10, 1946 2,590,853 Fulton Apr. 1, 19522,604,75 6 Greenland July 29, 1952 2,668,416 Lee Feb. 9, 1954 2,832,193Wood Apr. 29, 1958 2,856,910 Goodridge Oct. 21, 1958 2,871,844 Elliottet al Feb. 3, 1959

